Wednesday, 23 January 2013

Vitamin A:
The best source of knowledge on vitamin A seems to be the Weston A Price Foundation, which recommends at least 10,000IU for all adults (double that for pregnant/lactating women, half that for children <12 years old). This is much more than the USDA's upper limit, but so is the amount of saturated fat and cholesterol in this diet :P But if one is only getting the USDA RDA then it's likely to be enough to avoid strict deficiency, but not optimum.

Vitamin D:
Actually a hormone and not really a nutrient. We get most of our need for this of from the sun, but some people can be deficient. It's best to get a blood test and supplement based on your levels. The Vitamin D Council recommends everyone take 1,000IU per 25lbs body weight (6kIU per 150lbs) and that the ideal level is ~50ng/ml or 145nmol/l. I took 5,000IU at more than 150lbs, and after a year had levels tested and result simply said '>200nmol/l' so clearly this to too much for me. Always go off your blood levels, not a specific IU recommendation!

Vitamin E:Dr Udo says in his book "Fats that Heal Fats that Kill" that we need 0.65mg(?IU?) of vitamin E per gram of PUFA. This is a much better start for establishing a proper RDA for vitamin E compared to a flat 15mg RDA.

My diet version 2 gives 70% of that. As Udo is dealing with refined seed oils then the need of vitamin E is quite likely to be higher than with animal fats as saturated fats protect PUFAs from being oxidised. Udo's oil is 12.8/20.4/66.8% sat/mono/pufa with a omega-6:3 ratio of 0.44, while my diet is 47.3/47.6/5.1% and has a ratio of 2.3; as my diet has 3.7 times the saturated fat so the amount of vitamin E needed per PUFA may be as little as ~0.18mg/g. Using PUFA as a basis, my diet has ~7.6% the PUFA as his oil so this would mean vitamin E need is ~0.05mg/g PUFA.

Additionally the increased levels of glutathione (the most potent antioxidant in our body) on a carnivore diet due to increased intakes of cysteine, methinoine, and glycine (from meat, eggs, and gelatin respectively), means that the PUFA will be less prone to oxidation once in our blood. Some vitamin E or saturated will still be needed to prevent oxidation during storage and cooking though, but I'm perfectly happy that the vitamin E requirement is so low it's not worth worrying about as there are so many other protective systems in place.

Vitamin K1:

One major issue with a carnivore diet is lack of plants containing vitamin K1, animals foods contain no K1. Vitamin K1 is needed for coagulation, or is it? This study suggests that K2 can provide this function of K1, making K1 requirement nil in a carnivore diet providing plenty of K2.

Vitamin K2:

Vitamin K2 can be synthesised by healthy gut bacterai but they need K1 as a starting point sadly. OTher sources include fats, especially dairy fats, grass-fed fats and feremented fats. I'm having a lot of toruble finding the specific amount of K2 needed but that may be because it's a very new vitamin and so little is known about it. Assuming the K1 requirement should be replaced wholely by K2, then this means ~80ug for adult, 150ug for eldery people.

Where can be find that much?
105g hard cheese a day will give you 80ug, 533g butter (grass-fed is better) or a similar amount of egg yolks, pastured egg yolks are better needing only ~249g. (source) The WAPF recommends taking high-vitamin butter oil which is a natural concentration of vitamin K2, but that it's not needed if one if eating a lot of grass-fed fats.

Supplementing:
Taking 1mg every 2 weeks gives an average of ~71ug per day, which in addition to the fats and egg yolks in the diet will provide ample amounts. But this is very unlikely to be needed because of the increased absorption from a high-fat anti-nutrient-free diet.

I would say not to worry about vitamin K2 though due to increased absorption but our knowledge on this vitamin is severely lacking. Watch this space, as they say.

If you have osteoporosis or arterial calcification then supplementing is advised up to 5mg a day may be needed in extreme cases if a VLC/ZC ketogenic diet doesn't help.

Caveat:
The WAPF warns not to take vitamin A without vitamin D, and not to take vitamin D without K2. So if you're deficient in vitamin D, don't eat liver just yet, and make sure to always eat plenty of animal fats, preferably grass-fed or cheese.

We already looked at how we manage without the ability to synthesise ascorbic acid aka vitamin C, by using uric acid derived from protein instead, but why do we do this? Why not just make vitamin C like other carnivores do? Indeed all carnivores make ascorbic acid, so why are we different?

I believe that our lower level of gluconeogenesis (GNG) is to blame. Ascorbic acid is synthesised from glucose, and with a diminished capacity to make glucose then we don't really have any spare, the muscles need all they can get. So to converse the precious small glucose pool we switched from using ascorbic acid (derived from glucose) to uric acid (derived from protein), and one big difference is the amount of the substance needed for the same anti-oxidant potential.

Most animals synthesise tens to hundreds of grams (not milligrams of ascorbic acid daily, where-as in humans if we supplement 10 or more grams we can experience diarrhoea from too much vitamin C (less on a ketogenic diet). It's almost as if the body doesn't want extra vitamin C, and high levels can only be achieved through IVs. Amounts over 1.5mg/dL (or 1.3mgdL in females) is rapidly excreted through the urine (this is about 75mg (or 65mg in females) in the whole blood) with a half life of about 15 minutes, this is less than the USDA RDA at 90mg (75mg for females)! The body is actually very good at maintaining tight levels of ascorbic acid in the blood, and the daily turn-over on a vitamin C free diet (but grain-rich) can be as little as 2.5mg, so perhaps even less on a ketogenic diet.

Where-as the amount of uric acid in the blood ranges from 3mg/dL to 7mg/dL in males and 3mg/dL to 6mg/dL in females (150-350mg or 150-300mg in the whole blood). Also although 'hyperuricaemia' (high uric acid levels) is set at 6 or 7 mg/dL, some people can have as high as 9.6mg/dL and not develop gout. Vegetarians can have as little as 2.7mg/dL uric acid.

So a normal uric acid level is two to ~4.5 times as much as the saturation level of ascorbic acid!

Not only do we not make ascorbic acid (because of lowered GNG) but the blood has very low saturation levels compared to uric acid and excess is rapidly excreted, excess uric acid is less easily excreted suggesting a preference for higher levels. This further supports by theory that uric acid replaced ascorbic acid in humans.